Nilson Oleskovicz

Relative potency of ketamine and S(+)‐ketamine in dogs

The aim of this study was to determine the relative potency of racemic ketamine and S(+)-ketamine for the hypnotic effect and to evaluate the clinical anesthesia produced by equianesthetic doses of these two substances in dogs. One hundred and eight dogs were allocated in groups R2, R2.5, R3, R6, R9, R12, S2, S2.5, S3, S6, S9, and S12, to receive by intravenous route 2, 2.5, 3, 6, 9, and 12 mg/kg of ketamine or S(+)-ketamine, respectively. A dose-effect curve was drawn with the dose logarithm and the percentage of dogs that presented hypnosis in each group. The curve was used to obtain a linear regression, to determine the effective doses 100 and the potency relationship. In another experimental phase, eight groups of five dogs received 3, 6, 9 and 12 mg/kg of ketamine or S(+)-ketamine to evaluate the periods of latency, hypnosis, and total recovery. The times in which the dogs reached the sternal position, attempted to stand up for the first time, recovered the standing position, and started to walk were also recorded. The hypnotic dose for ketamine was 9.82 +/- 3.02 (6.86-16.5) mg/kg and for S(+)-ketamine was 7.76 +/- 2.17 (5.86-11.5) mg/kg. The time of hypnosis was longer in R3 and the first attempt to stand up occurred early in R6 when compared with S3 and S6 respectively. When R9 (100% of hypnosis with ketamine) and S6 [100% of hypnosis with S(+)-ketamine] were compared (1:1.5 ratio), the time to sternal position (12 +/- 2.5 and 20.2 +/- 5.6 min respectively) and the total recovery time (45 +/- 5.5 and 60.2 +/- 5.2 min respectively) were significantly shorter with S(+)-ketamine. It was concluded that the potency ratio between ketamine and S(+)-ketamine in dogs is smaller than the one reported in other species, and that the dose obtained after a reduction of 50%, as usually performed in humans, would not be enough to obtain equianesthetic effects in dogs.

Associação de cetamina S(+) e midazolam pelo método convencional de cálculo e pela extrapolação alométrica em bugios-ruivo (Alouatta guariba clamitans): resposta clínica e cardiorrespiratória

O objetivo deste estudo foi avaliar o protocolo de contencao quimica com cetamina S(+) e midazolam em bugios-ruivos, comparando o calculo de doses pelo metodo convencional e o metodo de extrapolacao alometrica. Foram utilizados 12 macacos bugios (Alouatta guariba clamitans) higidos, com peso medio de 4,84±0,97kg, de ambos os sexos. Apos jejum alimentar de 12 horas e hidrico de seis horas, realizou-se contencao fisica manual e aferiram-se os seguintes parâmetros: frequencia cardiaca (FC), frequencia respiratoria (f), tempo de preenchimento capilar (TPC), temperatura retal (TR), pressao arterial sistolica nao invasiva (PANI) e valores de hemogasometria arterial. Posteriormente, os animais foram alocados em dois grupos: GC (Grupo Convencional, n=06), os quais receberam cetamina S(+) (5mg kg-1) e midazolam (0,5mg kg-1), pela via intramuscular, com doses calculadas pelo metodo convencional; e GA (Grupo Alometria, n=06), os quais receberam o mesmo protocolo, pela mesma via, utilizando-se as doses calculadas pelo metodo de extrapolacao alometrica. Os parâmetros descritos foram mensurados novamente nos seguintes momentos: M5, M10, M20 e M30 (cinco, 10, 20 e 30 minutos apos a administracao dos farmacos, respectivamente). Tambem foram avaliados: qualidade de miorrelaxamento, reflexo podal e caudal, pincamento interdigital, tempo para inducao de decubito, tempo habil de sedacao, qualidade de sedacao, e tempo e qualidade de recuperacao. O GA apresentou menor tempo para inducao ao decubito, maior grau e tempo de sedacao, bem como reducao significativa da FC e PANI de M5 ate M30, quando comparado ao GC. Conclui-se que o grupo no qual o calculo de dose foi realizado por meio da alometria (GA) apresentou melhor grau de relaxamento muscular e sedacao, sem produzir depressao cardiorrespiratoria significativa.

Efeitos sedativos da associação de Cetamina e Midazolam administrados pela via intranasal ou intramuscular em papagaio (Amazona aestiva e Amazona vinacea)

A falta de protocolos de sedacao seguros para uso em papagaios na literatura demonstra a necessidade de conhecer os anestesicos que sao eficazes nestes animais. Devido a pouca massa muscular desta especie, notou-se a necessidade de estudar outra via de administracao, menos invasiva e dolorosa ao animal, como a via intranasal. O objetivo deste estudo foi avaliar os efeitos sedativos e a viabilidade da administracao intranasal, em comparacao a via intramuscular, de 15mg/kg de Cetamina e 1mg/kg de Midazolam. Foram utilizados 14 papagaios das especies Amazona aestiva e Amazona vinacea, de ambos os sexos, adultos, peso medio de 388,5±29,1g. Os animais foram distribuidos aleatoriamente em dois grupos: intramuscular (IM, n=7) e intranasal (IN, n=7). No grupo intramuscular, a administracao dos anestesicos foi realizada nos musculos peitorais, utilizando seringas de insulina e no grupo intranasal, com auxilio de uma micropipeta. Avaliou-se o periodo de latencia, tempo de duracao, qualidade de sedacao, e o tempo de recuperacao total. A media para o periodo de latencia no grupo IM foi de 6,13±2,02 minutos e no grupo IN de 4,84±2,37 minutos. Ja para o tempo de duracao da sedacao no grupo IM a media foi de 35,81±29,56 e no grupo IN de 24,52±14,83 minutos. Ambas as vias promoveram sedacao adequada, pois a media do escore da qualidade de sedacao obtida pelo grupo IM foi 2±1,5 e pelo grupo IN 1,28±1,1. O tempo de recuperacao total no grupo IM foi de 27,04±11,69 e no grupo IN de 17,67±11,64 minutos. Apesar do grupo IN ter apresentado os menores tempos de periodo de latencia, duracao e de recuperacao total e ter obtido melhor escore na qualidade de sedacao, nao houve diferenca estatistica significativa entre os grupos. Os resultados obtidos neste estudo indicam que a administracao de 15 mg/kg de cetamina e 1mg/kg de midazolam pela via intranasal ou intramuscular em papagaios (Amazona aestiva e Amazona vinacea) produzem sedacao adequada para pequenos procedimentos como colocacao de anilha, coleta de sangue e radiografias; porem a via intranasal mostrou ser uma alternativa menos invasiva quando comparado a via intramuscular.

Neoformação óssea e osteointegração de biomateriais micro e nanoestruturados em ovinos

A substituicao de parte do tecido osseo se faz necessaria muitas vezes na rotina cirurgica, seja em funcao de fraturas, neoplasias osseas ou enfermidades ortopedicas que acarretem em perda ossea. Neste sentido, tem se buscado biomateriais capazes de promover esta substituicao, evitando o uso de enxertos ou transplantes osseos. O objetivo deste trabalho foi avaliar a capacidade osteoregenerativa de biomateriais em diferentes composicoes, em tibias de ovinos. Foram utilizadas oito ovelhas mesticas texel, com 12 meses de idade e peso medio de 28,5±7,4kg. Apos adequada preparacao anestesica e cirurgica, foram produzidos tres defeitos osseos na diafise das tibias em sua face medial, totalizando seis defeitos de 6mm cada, sendo que quatro foram preenchidos por biomateriais, e dois por fragmentos osseos retirados do proprio animal (autocontrole). Os materiais implantados foram: hidroxiapatita (HA), tricalcio fosfato-β (TCP-β), hidroxiapatita/tricalcio fosfato-b 60/40 (HA/TCP-b 60/40) e o nanocomposito hidroxiapatita/alumina a 5% (HA/Al2O3 a 5%). Os animais foram alocados em dois grupos: Grupo 60 (n=04), em que os animais foram eutanasiados apos 60 dias da colocacao dos implantes e Grupo 90 (n=04), em que a eutanasia ocorreu 90 dias apos a colocacao dos implantes. Foram realizadas radiografias nos periodos pre-operatorio, imediatamente apos o procedimento e aos 30, 60 e 90 dias de pos-operatorio, a fim de excluir qualquer alteracao previa ou complicacao pos-operatoria, capaz de comprometer o estudo. Apos a eutanasia, foram coletadas as tibias para avaliacao macro e microscopica, por meio de microscopia eletronica de varredura (MEV) e microscopia optica. Os resultados encontrados mostraram uma boa capacidade de neoformacao ossea e uma lenta absorcao da HA. O TCP-β foi rapidamente absorvido e apresentou boa capacidade osteoindutiva e osteocondutiva, sendo observada neoformacao ossea no interior dos grânulos deste biomaterial. O composto bifasico HA/TCP-β (60/40) apresentou o melhor resultado a longo prazo, devido ao melhor controle na solubilizacao e liberacao dos ions calcio e fosfatos para o meio biologico durante o processo de neoformacao ossea. O biomaterial nanocomposito HA/Al2O3 a 5% nao apresentou resultados promissores neste estudo, e sugerem-se novas pesquisas a fim de investigar melhor o potencial e aplicabilidade deste novo biomaterial. Conclui-se que a hidroxiapatita, o tricalcio fosfato-β e a associacao HA/TCP-β (60/40) apresentam excelente capacidade de reparacao ossea, podendo ser utilizados como substitutos osseos; a associacao HA/TCP-β (60/40) e o melhor dentre os biomateriais estudados, pois apresenta velocidade de absorcao intermediaria em relacao a HA e ao TCP-β isolados, fornecendo ainda uma sustentacao adequada ao tecido neoformado; o biomaterial HA/Al2O3 5% se mostrou incompativel, provocando reacao de rejeicao por parte do hospedeiro e com insignificante formacao de tecido osseo, sugerindo novas pesquisas acerca deste material.

Efeitos anestésicos da administração intranasal ou intramuscular de cetamina S+ e midazolam em pomba-rola (Streptotelia sp.)

The intranasal route is a good alternative because is painless and easy to perform in birds. The objective of this study was to evaluate the anesthetic effects of S+ ketamine and midazolam administered by intranasal or intramuscular route in pigeons. Twelve animals were used in a randomized and crossover design. Animals received two treatments with 2-weeks interval. IM group: animals received 20mg/kg of S+ ketamine and 3.5mg/kg of midazolam by intramuscular route (pectoral muscles); IN group: animals received the same protocol by intranasal route. Parameters evaluated were: onset of action, time of duration in dorsal recumbency; total time of anesthesia and side effects. Statistical analysis was performed using Wilcoxon test and the differences were considered significant when P<0.05. Onset of action was 30 [30-47.5] and 40 [30-50] seconds for IM and IN respectively. Time of duration in dorsal recumbency was 59 [53.25-65] and 63 [37-71.25] minutes for IM and IN respectively, without significant differences between treatments. Total time of anesthesia was 88 [86.25-94.5] and 68 [53.5-93] minutes for IM and IN, respectively, with significant difference between groups. The recovery time was lower for IN (15[4.25-19.5] minutes) compared with IM (32 [28.25-38.25] minutes). Two animals of each group presented regurgitation in the recovery period. It was concluded that S+ ketamine and midazolam administered intranasal is an acceptable method of drug delivery and can be used to promote anesthesia in pigeons.

Dexmedetomidina epidural em gatas submetidas à ovariosalpingohisterectomia sob anestesia total intravenosa com propofol e pré-medicadas com cetamina S(+) e midazolam

The objective of this study was to evaluate the effect of the epidural administration of dexmedetomidine in cats submitted to ovariohisterectomy, under continuous infusion of propofol. The cats received S(+) ketamine (5mg kg-1) and midazolan (0.5mg kg-1) as premedication by intramuscular injection, and propofol as induction agent (4mg kg-1), by intravenous injection. After that, the cats were intubated and kept on oxygen 100%. Subsequently the continuous infusion of propofol was initiated (0.3mg kg-1 min-1). The animals were divided into two groups, in the dexmedetomidine group (DEXG, n=6,2µg kg-1) dexmedetomidine was administered by epidural injection, and in the control group (SALG, n=6) saline solution was administered by the same way. In both groups the final volume was 0.26 mL kg-1 completed with NaCl 0.9%. Fentanyl administration was necessary at T10 in 33.3% of the patients. During the continuous infusion of propofol, the medial palpebral reflex was present in 66.6% of the animals of SALG and in 16.6% of the animals of DEXG. The eyeball was centralized in all the animals of SALG and 83.4% of the animals of DEXG the eyeball were with ventral rotation. Reduction of the heart rate was observed after anesthesia induction in both groups. The mean arterial pressure was significantly lesser at T0 and T5 in the DEXG and greater at T10 in the SALG when compared to the basal values. The respiratory rate was lesser in the DEXG at T20 and T30 when compared to SALG. The SaO2 and PaO2 were bigger from T5 to T40. The PaCO2 bigger values were observed at T5, T10, T20, T30 and T40 for the DEXG and at T5, T10 and T20 in the SALG when compared to the basal values. In the anesthetic recovery, 50% and 16.6% of the animals presented aggressiveness in the SALG and DEXG, respectively. To the wound pain threshold, it was observed that 33.3% of animals of SALG and 66.7% of the animals of DEXG received score 0 (without reaction). It was concluded that the animals that received dexmedetomidine administration by epidural injection, presented more stable anesthetic plan with greater analgesia degree in the peri and postoperative period, better quality anesthesia recovery, and without significant cardiovascular and hemogasometric changes.

Azaperone e sua associação com xilazina ou dexmedetomidina em suínos

The aim of this study was to evaluate the sedative effects of azaperone and its association with xylazine or dexmedetomidine in swine, as well as verifying the possibility of the butyrophenone agent to counterbalance the effects caused by α2-adreneceptor agonists on the cardiovascular and hemodynamic parameters. For this, eighteen healthy swines of the Dambread X MS 50 lineage aged 50 days-old, weighing around 17.3kg (±1.7) were used. All animals were submitted an isoflurane anesthesia by face mask throughout the period of instrumentation. Basal parameters were measured 30 minutes after recovering from general anesthesia. All swines were randomly assigned into three groups of six animals each: AG (azaperone 2mg kg-1 + sodium chloride 0.5ml - IM), ADG (azaperone 2mg kg-1 + dexmedetomidine 3µg kg-1 - IM) and AXG (azaperone 2mg kg-1 + xylazine 2mg kg-1 - IM). Parameters were again measured at the following times: 15, 30, 45 and 60 minutes after administrating the corresponding drugs to each group. The heart rate had its values reduced in all groups; however this reduction was more significative in AXG. During the study was not observed a biphasic effect over the arterial pressure with an initial increase followed by a gradual decrease. AXG presented reduction of PaO2 and an increase in PaCO2 as well as a better sedative effect. The results allow to conclude that the association of azaperone with xylazine promoted a better tranquilization and muscular relaxation.

Meloxicam subaracnoide não inibe a hipernocicepção mecânica no teste da carragenina em ratos

BACKGROUND AND OBJECTIVE Evaluate the antinociceptive effects of subarachnoid meloxicam on the mechanical hypernociception induced by carrageenan in rats. METHODS Randomized controlled trial. Eighteen adult male Wistar rats underwent a cannula implantation into the subarachnoid space and were randomly divided into two groups: Group I (GI) received saline solution 5μL, while Group II (GII) received meloxicam 30mg. The mechanical hypernociception was induced by intraplantar injection of carrageenan and evaluated using a digital analgesymeter every 30minutes during a 4 hour period. The results were recorded as the Δ withdrawal threshold (in g), calculated by subtracting the measurement value after RESULTS The Δ withdrawal threshold mean values were lower in the group of patients treated with meloxicam over all time points between 45 and 165minutes, however, there was no statistical significance, (p=0.835) for this difference. CONCLUSION Subarachnoid meloxicam at a dose of 30μg.animal(-1) did not suppress the mechanical hypernociception in a model of inflammatory pain induced by intraplantar administration of carrageenan in rats. The data suggest that other dosages should be investigated the drug effect is discarded.

Farmacocinética do propofol em nanoemulsão em gatos

Propofol nanoemulsion is a new formulation consisting of nanoemulsified systems, characterized by the absence of lipid vehicle. Changes in drug vehicle may alter the pharmacokinetics and result in different distribution and elimination rates of propofol. The aim of this study was to evaluate the pharmacokinetics of a new oil in water propofol nanoemulsion formulation, compared to the traditional lipid emulsion. Six neutered female mixed-breed dogs were used (10.7±1.5kg) in a randomized and self control trial with 30 days interval. They received both propofol formulations administered as a bolus dose of 8mg kg-1 followed by 60 minutes continuous infusion at 0.4mg kg-1 min-1 rate. Arterial blood samples were collected just before induction (0), 2, 5, 10, 15, 30, and 60 minutes after the bolus dose, and after the end of the infusion at five, 10, 15, 30, 60, and 90 minutes and 2, 3, 4, 6, 10, and 24 hours. There were no significant differences in the evaluated pharmacokinetics parameters that included volume of distribution, clearance, elimination rate constant, half-life, and distribution constants, demonstrating that propofol nanoemulsion has no pharmacokinetics differences when compared to the traditional formulation.

Índice de mortalidade durante procedimentos anestésicos: estudo retrospectivo (1996-2006)

O objetivo deste estudo e reportar a incidencia de obitos anestesico-cirurgicos durante um periodo de 11 anos (1996-2006), no qual nao eram realizados exames complementares e/ou laboratoriais previamente ao encaminhamento para anestesia. Dessa forma, realizou-se um estudo retrospectivo, avaliando-se as fichas anestesicas utilizadas durante os procedimentos realizados no Hospital de Clinica Veterinaria (HCV) da Universidade do Estado de Santa Catarina (UDESC). Analisaram-se 7.012 procedimentos anestesicos, sendo 5.500 (78,4%) realizados em caes e 1.512 (21,6%) em gatos, submetidos a anestesia geral. Os obitos considerados foram os ocorridos durante os periodos trans-anestesico e o pos-operatorio imediato, nao sendo levada em consideracao a classificacao da American Society of Anesthesiologists (ASA), a idade dos pacientes, o sexo ou procedimento cirurgico realizado. Todos os animais foram submetidos aos procedimentos anestesico-cirurgicos somente com avaliacao clinica pre-anestesica, sem exames complementares previos, e foram monitorados no periodo trans-anestesico, tomando-se como base a anestesia clinica. Nesse periodo, observaram-se 63 obitos decorrentes da anestesia, sendo 49 em caes (77,8%) e 14 em gatos (22,2%). O indice de mortalidade observado em caes foi de 0,89% e, em gatos, de 0,92%. O protocolo anestesico com maior indice de mortalidade em caes foi a associacao atropina, xilazina, tiopental e halotano (20,4%), nao havendo um protocolo de destaque em relacao a esse indice nos gatos. Os farmacos associados com maior taxa de mortalidade foram diazepam, etomidato e isofluorano, tanto para caes, quanto para gatos, quando analisados individualmente.